A 55 is not a great tank shape in all honesty, they're too narrow for good aquascaping. You can stick the same kit you have on a 55 straight on a 75 or 90 and get all the advantages of the extra water volume for no great financial loss. That's especially true of the lighting, and it might actually be easier to get good flow in a 90 than a 55 with the extra space to push water around in . The only thing you might need to alter is your skimmer choice.
One of the huge benefits of sump systems is the choice of good skimmers open to you is so much wider than relying on a comparatively small number of decent HOB's. The price for these is often pretty competitive too, especially second hand. I got a second hand schuran for very little - it's ugly, very traditional, and will outskim any HOB to oblivion - the fact it's totally ugly, nonHOB, purely functional makes it total bang for the buck